Reverse String

				
					// using Arrow Function + built-in functions
const reverseStr = (str) {
    return str.split("").reverse().join("");
}

// using function declaration
function reverseStr(str) {
    return str.split("").reverse().join("");
}

Write a program to reverse a string by words. Also show the reverse of each words in place

				
					const str = "JavaScript is awesome";
str.split(" ").reverse().join(" ");                                             // "awesome is JavaScript"

const str = "JavaScript is awesome";
str.split(" ").map(val => val.split("").reverse().join("")).join(" ");          // "tpircSavaJ si emosewa"

Write a program to reverse a given integer number

				
					let num = 3849;

let reversedNum = 0;
while(num !== 0){
    reversedNum = reversedNum * 10 + num % 10;
    num = Math.floor(num / 10);
}

reversedNum;                                        // 9483

let num = 3849;

let numStr = String(num);
+numStr.split("").reverse().join("");               // 9483

Write a code to replace all the spaces of the string with underscores

				
					str.split(" ").join("_");

str.replaceAll(" ", "_");

Write a function which can convert the time input given in 12 hours format to 24 hours format

				
					// Example
convertTo24HrsFormat("12:10AM");    // 00:10
convertTo24HrsFormat("5:00AM");     // 05:00
convertTo24HrsFormat("12:33PM");    // 12:33
convertTo24HrsFormat("01:59PM");    // 13:59
convertTo24HrsFormat("11:8PM");     // 23:08
convertTo24HrsFormat("10:02PM");    // 22:02

function convertTo24HrsFormat(timeText) {
  var timeTextLower = timeText.toLowerCase();
  let [hours, mins] = timeTextLower.split(":");

  // 12 o clock is the special case to be handled both for AM and PM
  if (timeTextLower.endsWith("am"))
        hours = hours == 12 ? "0" : hours;
  else if (timeTextLower.endsWith("pm"))
        hours = hours == 12 ? hours : String(+hours + 12);

  return hours.padStart(2, 0) + ":" + mins.slice(0, -2).padStart(2, 0);
}